High efficiency plasma creation system and method

ABSTRACT

A chamber cross-sectional multi-stage plasma arrangement characterized by escalating charge movement towards chamber center axis through one or more escalation stages contributing to the heating of the plasma, the centering of the plasma on the chamber axis, and creating rotation of the plasma therein. Rotation of the plasma around its axis induces a self-generated magnetic field, which in turn increases plasma stability and confinement. Some of the said stages of the multi-stage arrangement may be created by physical elements and components while others may be induced or generated by externally applying magnetic and/or electric fields or their combinations and/or by injection of electrons, ions or other plasma.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention is filed under 35 U.S.C. § 371 as the U.S.national phase of International Application No. PCT/IL2021/051541, filedDec. 27, 2021, which designated the U.S. and claims the right ofpriority of Israeli patent application 281747 filed with the IsraeliPatent Office on Mar. 22, 2021. The entire disclosures of theabove-identified priority applications are hereby fully incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates to a relatively small linear stable plasmaconfinement systems and methods for the harvesting of various types ofproducts and effects derivable from such phenomena.

BACKGROUND OF THE INVENTION

Plasma is a highly ionized gas containing an approximately equal numberof positive ions and electrons. A plasma is electrically conductive, andcan, therefore, be manipulated by electrical or magnetic fields.Obtaining a stable plasma at such operable temperatures is a challengemuch discussed in the art. Current systems and methods to such end arecomplex, require very large physical installations and do not presentcommonly commodified applicable means to harvest the widely knownbenefits and advantages of such phenomena.

Since plasma is an electrical conductor, it is possible to heat theplasma by inducing a current through it; the induced current thatprovides most of the poloidal field is also a major source of initialheating. The heating caused by the induced current is called ohmic (orresistive) heating. The generated heat depends on the resistance of theplasma and the amount of electric current running through it. But as thetemperature of heated plasma rises, the resistance decreases and ohmicheating becomes less effective.

A great many number of plasma sources have been suggested and developed.The variety of plasma sources differ in the methods of plasma excitationand the geometry of the electrodes and plasma volume, which in turn,determine major parameters of the plasma.

Some such methods and systems consist of various gaseous components andmixtures thereof as an ion source which when coupled with an energysources creates an ionized gas which is guided and or confined bymagnets or any other means suitable for creating a magnetic field,wherein energizing the ions to the energy necessary for the intendedreaction is obtainable in the prior art by different combinations ofelectric or magnetic fields, arrangements of electrodes and the like.Thus creating emission such as X-Rays, extreme UV, neutrons and thelike.

The following are some terms and phenomena recognized in the relevantart:

Pinch—a current in the plasma can create a field that may be strongenough to self-confine the plasma while decreasing or totally removingthe need for external magnets to confine the plasma. The possibility toperform a “pinch” in the plasma enables replacing the use of a toroidalshape with a cylindrical one. Instead of a large toroid, one couldsimply induce the current into a linear tube, which could cause theplasma within to collapse down into a filament. This has the advantagethat the current in the plasma would heat it through normal resistiveheating, but this configuration is considered in the prior art to beconsiderably limited in the attainable plasma temperature. However, asthe plasma collapses, the adiabatic process would result in thetemperature rising dramatically. Another way to create a pinch is byincreasing the magnetic field in a very high pulse of current inside thecoils that create the magnetic field. This pinch increases the pressureon the plasma and therefore increases the plasma density.

Magnetic Compression—A gas can be heated by sudden compression. In thesame way, the temperature of a plasma is increased if it is compressedrapidly by increasing the confining magnetic field. Since plasmacompression brings the ions closer together, the process has theadditional benefit of facilitating attainment of a required density. Itis known in the art that magnetic compression was implemented in limitedscope in the ATC (Adiabatic Toroidal Compressor), though the concept hasnot been widely used since then.

Plasma stability—plasma may be subject to perturbative forces which mayaffect its equilibrium. In a stable plasma such perturbations will bedamped or cancelled out resulting in plasma parameter stability,stability for a set period of time.

To increase plasma stability in FRC (where high energy ensues kineticeffects) a “stabilized pinch” was conceptualized: this concept addedadditional magnets to the outside of the chamber, which created a fieldthat would be present in the plasma before the pinch discharge. In mostconcepts, the external field was relatively weak, and because a plasmais diamagnetic, the external magnetic field penetrated only the outerareas of the plasma. When the pinch discharge occurs and the plasmaquickly contracts, this field became “frozen in” to the resultingfilament, creating a strong field in its outer layers. This is alsotermed as “giving the plasma a backbone”.

In the toroidal configuration, stabilization was slightly different: thelayout would be the same as the stabilized pinch configuration, but therole of the two fields would be reversed. Instead of weak externalfields providing stabilization and a strong pinch current responsiblefor confinement, in the new layout, the external magnets would be muchmore powerful in order to provide the majority of confinement, while thecurrent would be much smaller and responsible for the stabilizingeffect.

FRC—Field Reversed Configurations—moving current generates a magneticfield around itself. That magnetic field can self-contain the current.Field Reversed Configurations are loops of charged plasma. They maketheir own magnetic fields, self-containing themselves. On the inside ofthe loop, the plasma density is higher. An FRC is a structure made fromplasma. FRC can be obtained in a toroidal machine as well as in a linearmachine.

Various approaches to obtain FRC in linear machines are known. One suchapproach is by magnetic field ion mirroring at corresponding ends of alinear machine which causes the plasma to bounce back and forth betweenthe bundled ends of the linear machine thereby forming an FRC in themiddle of the machine. The two magnetic mirrors at the ends of thelinear chamber face one another while a rotating magnetic field isapplied on the outside of the tube chamber. This arrangement pulls theelectrons in the plasma along—making a current which in turnself-generates a magnetic field forming an FRC in the middle of theplasma.

Another approach would be by firing two neutral beams of gas at themiddle of the cylindrical chamber in a slight angle that will eventuallycause the plasma to rotate and create an FRC. These beams also heat theplasma by collisions and are ionized to further increase the density.

Current solutions known in the art for creation of stable, efficientharvestable plasma present many problems and limitations. For instance,it is known in the art that sometimes the energy may leak out in hugebursts. Furthermore, in such situations the current is induced bycontinually increasing the current through an electromagnetic windinglinked with a plasma torus: the plasma can be viewed as the secondarywinding of a transformer. This is inherently perceived as a pulsedprocess because there is a limit to the current through the primary(there are also other limitations on long pulses). Current systems knownin the art, must therefore either operate for short periods or rely onother means of heating and current drive. A drawback of such systems isthat a sudden impulse or loss of heat can destroy a component. Suchaccidental losses cannot be tolerated in a complex, expensive andsometimes hazardous system.

Another drawback in the art is the physical size of the actual systemneeded to produce plasma. Toroidal designed systems as well as somecurrently designed linear machines present challenges in obtainingplasma products of scale.

Stability is a precondition for effective plasma creation and harvestingprocesses. Current design of toroidal machines as well as that of linearmachines present challenges in obtaining a desired stability. It is wellknown in the art that linear axisymmetric systems can present highplasma stability due to its symmetry, nevertheless currently designedlinear systems obtain heating by indirect methods (such as ion beams, RFantenna, lasers) thereby adversely affecting the efficiency of theplasma heating. These indirect methods require high degrees of inputenergy, thus adversely affecting the overall efficiency of the system.

Although relatively small axial cylindrical inertial electricalconfiners are known in the art, such devices are not consideredadvantageous for plasma harvesting but, if at all, adequate for othertechnical tasks such as X-ray sources (‘A Portable Neutron/tunable X-raysource based on inertial electrostatic confinement’, Nucl. Instrum.Meth. Physics Res. A 422, 16-20, 1999).

There is a further need to provide a system and method configured tocope and mitigate said drawbacks and provide additional advantages.

SUMMARY OF THE INVENTION

The present invention provides a system and method for creating a localself-generated magnetic field arranged to contribute to a substantiallystable plasma and ion heating mechanism. Various combinations of sucharrangement provide for facilitation of high efficiency plasma processes(such as neutron sources, extreme UV, etching process, etc.).

The present invention substantially introduces the following aspects:plasma confinement; ion and/or electron heating in plasma; densityincreasing of plasma; high or extremely high stability of plasma; highlystable for relatively long periods of time (magnitude of milliseconds)plasma; and a mostly axial-symmetric chamber design. A relativelylong-term stable plasma is termed herein as Super Stable Confined Plasma(SSCP). The implementation of various combinations, partially or wholly,of these aspects of the present invention facilitates economical andhighly scalable efficient plasma and/or ion heating processes.

The present invention suggests a system and method which provides achamber cross-sectional multi-stage plasma arrangement characterized byescalating charge movement towards chamber center axis through one ormore escalation stages contributing to the heating of the plasma, thecentering of the plasma on the chamber axis, and creating rotation ofthe plasma therein. Rotation of the plasma around its axis induces aself-generated magnetic field, which in turn increases plasma stabilityand confinement (not un-similar to the well-known toroidal pincheffect). Some of the said stages of the multi-stage arrangement may becreated by physical elements and components while others may be inducedor generated by externally applying magnetic and/or electric fields ortheir combinations and/or by injection of electrons, ions or otherplasma.

The following embodiments and aspects thereof are described andillustrated in conjunction with systems, devices and methods which aremeant to be exemplary and illustrative, not limiting in scope. Invarious embodiments, one or more of the above-described problems havebeen reduced or eliminated, while other embodiments are directed toother advantages or improvements.

BRIEF DESCRIPTION OF THE FIGURES

Some embodiments of the invention are described herein with reference tothe accompanying figures. The description, together with the figures,makes apparent to a person having ordinary skill in the art how someembodiments may be practiced. The figures are for the purpose ofillustrative description and no attempt is made to show details of anembodiment in more detail than is necessary for a fundamentalunderstanding of the invention.

In the Figures:

FIG. 1 constitutes a schematic view of the high efficiency plasmasystem, according to some embodiments of the invention.

FIG. 2A-2B constitute schematic views of the high efficiency plasmasystem chamber, according to some embodiments of the invention.

FIG. 3A-3B constitute schematic views of the ionization stages in thehigh efficiency plasma system chamber reaction area, according to someembodiments of the invention.

FIG. 4A depicts axial section of Particle-In-Cell simulation results ofion acceleration in the high efficiency plasma system chamber reactionarea, according to some embodiments of the invention.

FIG. 4B depicts axial section of Particle-In-Cell simulation results ofelectron acceleration in the high efficiency plasma system chamberreaction area, according to some embodiments of the invention.

FIG. 4C depicts cross section of Particle-In-Cell simulation results ofion radial direction velocity in the high efficiency plasma systemchamber reaction area, according to some embodiments of the invention.

FIG. 4D depicts cross section of Particle-In-Cell simulation results ofion phi direction velocity in the high efficiency plasma system chamberreaction area, according to some embodiments of the invention.

FIG. 5A-5B constitute schematic examples of magnetic and electric fieldsobtainable upon operation of the high efficiency plasma system andmethod, according to some embodiment of the invention.

FIG. 6A is a photographic image of a test apparatus according to someembodiment of the invention showing the high efficiency plasma systemchamber reaction area looking along the chamber's axis line,demonstrating plasma circulation in a lower magnetic field.

FIG. 6B is a photographic image of a test apparatus according to someembodiment of the invention showing the high efficiency plasma systemchamber reaction area looking along the chamber's axis line,demonstrating plasma circulation in a higher magnetic field.

FIG. 7 is a chart of voltage measured in probes used in a test apparatusaccording to some embodiment of the invention versus externally appliedvoltage values.

FIG. 8A-8G show examples of electrode design according to someembodiments of the invention.

FIG. 9 constitutes a schematic example of obtainment of ion mirroringobtainable upon operation of the high efficiency plasma system andmethod, according to some embodiment of the invention.

FIG. 10A-10D show examples of mesh cylinder design according to someembodiments of the invention.

DETAILED DESCRIPTION OF SOME EMBODIMENTS AND EXAMPLES

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, and components,modules, units and/or circuits have not been described in detail so asnot to obscure the invention. Some features or elements described withrespect to one embodiment may be combined with features or elementsdescribed with respect to other embodiments. For the sake of clarity,discussion of same or similar features or elements may not be repeated.

Although embodiments of the invention are not limited in this regard,discussions utilizing terms such as, for example, “controlling”“processing,” “computing,” “calculating,” “determining,” “establishing”,“analyzing”, “checking”, “setting”, “receiving”, or the like, may referto operation(s) and/or process(es) of a controller, a computer, acomputing platform, a computing system, or other electronic computingdevice, that manipulates and/or transforms data represented as physical(e.g., electronic) quantities within the computer's registers and/ormemories into other data similarly represented as physical quantitieswithin the computer's registers and/or memories or other informationnon-transitory storage medium that may store instructions to performoperations and/or processes.

The term “controller”, as used herein, refers to any type of computingplatform or component that may be provisioned with a Central ProcessingUnit (CPU) or microprocessors, and may be provisioned with severalinput/output (I/O) ports, for example, a general-purpose computer suchas a personal computer, laptop, tablet, mobile cellular phone,controller chip, SoC or a cloud computing system.

Unless explicitly stated, the method embodiments described herein arenot constrained to a particular order or sequence. Additionally, some ofthe described method embodiments or elements thereof can occur or beperformed simultaneously, at the same point in time, or concurrently.

According to one aspect of the invention, an axial-symmetric shape ofthe plasma is maintained stable and coaxial by a combination of part orall of the following discussed system components or elements, asschematically exemplified in FIG. 1 , substantially consisting of—

-   -   (i) a cylindrical chamber (100) having substantially reduced        internal pressure;    -   (ii) inner anode element (145)    -   (iii) an electrode (140) positioned at each end of tubular        chamber connected to external power supply;    -   (iv) external solenoids or magnets or combination thereof (160);    -   (v) capacitor banks (for e/m pulse) external to chamber (800);    -   (vi) controlling unit (500);    -   (vii) very high quality vacuum (characteristically of 10⁻³-10⁻⁷        Torr) pumping system (600);    -   (viii) pre-heating electric power supply (700).    -   (ix) working gas source (900) coupled with a control valve (920)        connected to a gas inlet (910).

Reference is made to FIG. 2A whereby tubular chamber (100) is optionallycombined with an inner anode element (145) (proximal to the chamber'sinternal skin), as initial outer stage to inner cascaded stages ofexternal and inner generated or induced magnetic and electrical fields.While making reference to FIG. 2B wherein optional electrodes (140) atends of tubular chamber act as cathodes in ionization process.

Whereas in one embodiment, at least one inner tubular electric field iscreated by a conductive apparatus (135) or by “virtual” induced plasma(130) concentrically arranged on tubular chamber axis, wherein suchinner field acts as a cascaded stage manipulating the ionization. Makingreference to FIG. 3A showing the facilitation of Outer Ionization Stage(OIS) (300) which contributes to a high rate of ionization of theworking gas originating from working gas source (900) controllablyinjected into chamber (100) through control valve (920) via gas inlet(910). This ionization is due to the relatively high electric field(typically ˜2-7 kV but also much larger ranges such as ˜2-20 kV or evenlarger) in outer cascade. The coupling of such ionization with rotationof the electrons about the chamber axis (110) due to the externallyapplied electric field (from pre-heating power supply (700)) andmagnetic field (through magnetic coil or solenoids (160) coupled withcapacitor bank (800)) contributes to the heating of the ions in the OIS(300) and their acceleration towards the chamber axis (110). Suchacceleration which in itself contributes to gradient of a magnetic fieldleads to a compression of ions at and about chamber axis (110) andthereby contributing to the creation of stable plasma (130) at reactionarea (170), in accordance with controller unit (500) directions. Makingreference to FIG. 3B showing the facilitation of one embodiment, whereinat least two additional inner tubular electric fields are created byconductive apparatus (135) or by “virtual” plasma inducementconcentrically arranged on tubular chamber axis (110), such inner fieldsact as additional cascaded stages manipulating the ionization throughOuter Ionization Stage (OIS) (300) and Main Reaction Stage (MRS) (200).The upper parts of the cascaded stages, the OIS, contribute to a highrate of ionization of the working gas. This ionization is due to therelatively high electric field (typically ˜2-7 kV but also much largerranges such as ˜2-20 kV or even larger) generated in outer cascade.Electric field at inner cascade stage, at the MRS, is to be of muchlarger magnitude (typically ˜10-35 kV but also much larger ranges suchas ˜10-100 kV or even larger).

Such arrangements ensue electrons emitted from said optional electrodes(140) at ends of tubular chamber to create a “virtual cathode” (130) ataxis of tubular chamber affected by externally applied magnetic andelectrical fields coupled with the internally generated magnetic andelectrical fields, bringing about magnetic and electrical forces on gasions, in accordance with controller directions. As is demonstrated to beobtainable in FIG. 4A through FIG. 4D depicting certain Particle-In-Cell(PIC) simulation results conducted according to some embodiments of theinvention. It being understood by those skilled in the art that PICsimulations are acceptable investigation and demonstration for plasmasimulation techniques. FIG. 4A shows PIC simulation results of ionacceleration in the chamber (100) radial direction while FIG. 4B showsthe confining of electrons to two stages of potential well: at area(401) proximal to chamber wall; and at area (402) of chamber axis (110).FIG. 4A and FIG. 4B exemplify the phenomena that ions are less affectedby the magnetic field proportionate to their mass which is much heavierthan that of the electrons. Thereby the said arrangement wouldfacilitate the movement of ions between areas (401) and (402) as shownin FIG. 4A, while electrons substantially remain situated either inareas (401) or (402) as shown in FIG. 4B. Such PIC simulationdemonstrates the facilitation of the OIS (300) and “virtual cathode”(130) at axis of tubular chamber creating the MRS (200). The ionmovement characteristic ion (i) radial direction velocity is shown inFIG. 4C and ion (i) Phi direction (rotational) velocity in FIG. 4D, bothshown against the stagnant electrons (e) in areas (401) and (402)accordingly. It would be appreciated by a person skilled in the art thatsuch PIC simulations demonstrate the increased ion velocity, bothradially as well as or alternatively rotationally, which is indicativeof the high ion temperature obtainable at the chamber axis (110) area inthe said arrangement.

According to some embodiments, a cylindrical chamber is used toencapsulate the process. The chamber walls may be made of variousmaterials (varying from metals, ceramics, pyrex, glass and others).Different materials may have different advantages or disadvantages byway of strength, temperature conveyance, isolation, radiation“transparency”, “opacity” and other characteristics. According to someembodiments, chamber walls are conducive and may act as electrode (145)or as a stage in the cascade of magnetic and electrical fields.

According to some embodiments, cylindrical chamber (100) is initiallyhighly depressurized to very high quality vacuum conditions(characteristically of 10⁻³-10⁻⁷ Torr) prior to gas injection throughgas inlet (910) connected to a control valve (920) in order to preventinterference/contamination by undesired particles of residual gasses.According to some embodiments, cylindrical chamber is filled with aworking gas (Xenon/Argon/hydrogen/deuterium/or other relevant gases orcombinations thereof depending on the plasma process to be implemented)at a predefined pressure. Gas in the chamber is ionized and effectivelymanipulated by applied magnetic and electric fields arranged accordingto the invention.

According to some embodiments, the outer circumference of cylinderchamber (100) contains an active conducting component which acts as ananode allowing for the induction of a radial electric field of highvoltage that ionizes the gas in the chamber. Referring to FIGS. 2A and2B this component of the outer chamber (100) is the first stage of themulti-stage anode arrangement an example of which is shown in FIG. 2which comprises several stages of plasma some of which may be physicaland others may be “virtually” induced. According to some embodiments ofthe invention, referring to FIG. 3 , such stages are radially arrangedin relation to the chamber axis (110), each stage causing theacceleration of ions towards central axis in the area of which plasma(130) is concentrated.

It being appreciated by a person skilled in the art that ionacceleration may be obtained by various magnetic and electrical fieldsand their combinations, by way of an un-limiting example, makingreference to FIG. 1 , according to some embodiments, the reaction area(170) of the chamber circumference (100) is surrounded by a fairlymedium to low power magnet or magnetic coil (160) (typically of amagnitude of ˜0.1-0.5 Tesla or larger such as ˜0.1-2 Tesla). Accordingto some embodiments, such MRS is evident at the longitudinal center ofchamber and, according to some other embodiments, active part (170) mayextend to ends of tubular chamber (100) such as in area of electrodes(140). Substantially, such arrangement allows for the application of acurrent pulse in the coil which causes a magnetic pulse which in turncauses the plasma in the chamber to compress and heat to higherefficiency of plasma processes.

According to some embodiments, maintainability of the system is improveddue to its relatively small size. Pulse operated system enjoy prolongedlife span of materials which otherwise would deteriorate undercontinuous operation—thus reducing MTBF and due replacements;

According to some embodiments, a multi-stage ionization is outlined inFIG. 3A showing the internal area in which the axi-distal edge of thecylindrical grid element or of the “virtual mesh grid” operate as theboundary and the cathode of the outer ionization stage (“OIS”) steps-upthe plasma ionization level in the chamber which eventually increasesthe ion flux towards the axis of cylinder.

According to some embodiments, a multi-stage ionization is outlined inFIG. 3B showing the internal area in which the axi-distal edge of thecylindrical grid element or of the “virtual mesh grid” operate as theboundary and the cathode of the outer ionization stage (“OIS”) whichsteps-up the plasma ionization level in the chamber which eventuallyincreases the ion flux towards the material cathode or “virtual cathode”passing through the Main Reaction Stage (MRS) at the axis of cylinder.According to some embodiments, as outlined in FIG. 3A, the creation ofthe MRS and the “virtual cathode” coincide thereby increasing thedensity of ions in the axis creating a higher probability of reactionbetween accelerated ions from the OIS stage with the ions in thecombined MRS and “virtual cathode” volume. Ions passing under suchconditions (per FIG. 3A or FIG. 3B) contribute to the creation of thedesignated plasma processes.

According to some embodiments, internal volume where plasma isconcentrated, is surrounded by an internal metallic grid cylinder (135)(substantially lower than 15% mesh density and typically less than 5%mesh density). Metallic grid cylinder may be made of various materials(such as any conducting material that can withstand heat and has lowabsorption of water or other substances and will not contaminate thechamber, such as stainless steel, tungsten, molybdenum, and othermaterials) and be in various shapes and patterns (such as helical springshape, perforated, slotted, whole, flute, etc. as some such examples asexperimented are shown in FIG. 10A through 10D) (such internalcylindrical element is referred to hereinafter as “mesh cylinder” or“cylindrical grid element”).

According to some embodiments, instead of or in addition to thecylindrical grid element, an electromagnetic field may be locallygenerated producing a similar effect to that of a mesh cylinder (135) bymanipulation of the multi-stage anode arrangement.

According to some embodiments, said cylindrical grid elements plays alsothe role of an anode for the MRS. The result being a cascade of stagesthe first of which is the external chamber's cylinder acting as an anodeand the next being the cylindrical grid element anode. The next stagebeing a material cathode or a “virtual cathode” on axis of chambercylinder in area of plasma, such “cathodal” character resulting from theapplication of the prior stages coupled with the electron emissionelectrodes at ends of active tubular chamber. The cross-product of thelinear magnetic field flux in the chamber with a radial electric fieldwithin the chamber results in the creation of a strong internal magneticfield as schematically exemplified in FIG. 5A. This self-inducedmagnetic field (301) has closed field lines within the chamber. Suchcross-product contributes to the contortion and coaxilization of theplasma without investment of substantially additional energy. Adjustingand optimizing the electric and magnetic fields and their cross-productcreates strong confinement and thereby obtains high-pressurehigh-density highly-stable plasma (not un-similar to the conventionalFRC effect). According to some embodiments, making reference to FIG. 5B,whereupon additionally an external magnetic pulse 302A (typically ofmagnitude 3-10 Tesla or larger) would increase the induced current,which is the product of the external magnetic field pulse (302A) and theexternal electric field, apparent in the chamber axis (110) therebycontorting the axial plasma contributing to an SSCP effect presenting alongitudinally concentrate of induced magnetic field (301A). Such effectis also evident in photographic images of a working test apparatusarranged according to the invention presented in FIG. 6A and FIG. 6B.FIG. 6A and FIG. 6B are photographic images of a system according to theinvention showing the plasma circulating around the axis of the chamberunder different external magnetic field application. Evidently, theplasma (300B) radius is larger under the stronger externally appliedmagnetic field and smaller radius (300A) under a lower externallyapplied magnetic field. A person skilled in the art would appreciatethat the rotational energy is effectuated by the external radialelectric field and its product with the external magnetic field (ExB) inthe z direction (axial). Such change of the external magnetic fieldwould characteristically dominantly contribute to the creation of theSSCP effect as visually demonstrated in the plasma contortion shown inFIG. 6A and FIG. 6B. Furthermore, a person skilled in the art wouldappreciate that applying a strong pulse of external magnetic field willcreate the effect substantially equivalent to a Pinch compressing andovercoming the centrifugal forces of the plasma thereby bringing aboutthe heating of the plasma as well as increasing the plasma density inthe MRS and bringing the plasma to highly energetic parameters. Anexample of obtaining such energetic parameters is show in FIG. 7 whichpresents a chart of voltage measured in probes versus externally appliedvoltage values as per test apparatus according to some embodiment of theinvention. The test apparatus comprised of two Langmuir probes one ofwhich located at bottom area of OIS and the other at the top of MRSarea. The probes measured the plasma electric potential. FIG. 7 showsthe high correlation between applying various heating/accelerationvoltages to the measured plasma voltage which indicates the actualheating of the plasma at the MRS (200).

The acceleration of ions ensues an increase of temperature. Thisacceleration is a direct result of the static electric field which isconsidered to be an efficient method to provide kinetic energy to acharged particle. According to some embodiments, using the radialelectric field creates an innate axisymmetric heating mechanism having ahigh degree of uniformity, which maintains the axial symmetry which iscrucial for plasma stability.

A person skilled in the art would appreciate that plasma density may beincreased by injecting additional gas into chamber. According to someembodiments, gas injection can be achieved through the cylinder wall(100) by gas inlet connected to a proportional valve (920). Controllingthe injection of the gas through the chamber wall may further contributeto the effective distribution of the charged gas by way of influencingdensity disbursements in chamber volume.

According to some embodiments, electrodes (made of high temperatureresistant materials, such as Tungsten/Molybdenum/or the like) arecoaxially positioned at ends of tubular chamber and connected to highnegative voltage. Such designs may be used to contribute to the electricfield at the chamber axis and/or to facilitate as an electron emittingsource. According to some embodiments, such electrodes can be eitherpassive wherein heating is by the plasma itself from electrode tip (141)or active wherein the heating is externally induced in the electrode andthus actively causing emission of electrons from active electrode tip(141′) (creating an “electron gun”).

According to some embodiments, said electrodes are characterized by avarying gradients and/or gradual changing radii and/or varying planesdesign comprising of several phases of different magnitude scale.Reference is made to FIG. 8A through 8G showing some such electrodes.According to some embodiments such electrodes as shown in FIGS. 8B and8F may be characterized by three major areas of said phases: arelatively large magnitude phase (143); a mid-section phase taperingtowards tip (142); and a tip section phase (141). According to otherembodiments, additional alternate electrode designs are implementable(as may be shown in FIGS. 8A, 8C, 8D and 8E). Making reference to FIG.8G showing yet another electrode design combined with an internalheating element (147) which when heated instigates high rate of electronemission from electrode tip (141).

Making reference to FIG. 9 , an active electrode emits electrons fromactive tip (141). Such active emission is obtained by external heatingelement (700). The heat concentrated at the tip phase (141) causes theemission of electrons in a thermionic emission process. Thus, accordingto some embodiments of the invention, the emitted electrons arelongitudinally forced by the electric field and held by the magneticfield towards the middle of the chamber thus contributing to thecreation of an initial “virtual cathode” (130) and thereafter sustainingit at a substantially steady state.

According to some embodiments, the shape and structure of the electrodesimmersed within the volume of the chamber creates an electron “gun”source. According to some embodiments, the shape and structure of theelectrodes immersed within the volume of the chamber creates an“electric mirror” or “electric deflector” which is obtained by the saidunique specific geometric shapes according to the invention such as perFIG. 8A through 8G. Whereas, a person skilled in the art wouldappreciate that such effects may be obtained by other specificmulti-phased electrode designs in accordance with the invention.

By way of un-limiting example, reference is made to FIG. 9 which showsthe electric field back mirror (171) created when placing coaxiallyimmersed electrode (140) in chamber (100) aligned with its axis (110).In such example the plasma phase at its distal ends in area of electrodetip (141), placed at each end of chamber, accumulates a volume of ions.Making reference to FIG. 9 ion clouds (151), (152) and (153) which arenot captured into the main plasma flux have a containment effect on theplasma shape and form in the chamber. Such clouds are considered to havea “mirroring” constraining effect whereby ions in trajectory towardsends of tubular chamber are contained by the electron cloud (asschematically shown in FIG. 9 ). According to some embodiments, suchmirroring is obtained by the combination of the multi stage cascadearrangement in the chamber together with said multi-phased electrodes,without installing actual magnets at ends of linear design chamber toobtain a “magnetic mirroring effect” as may be suggested in othercylindrical designs. According to some embodiments, it is enough to relyon the electron emission from the plasma distal electrode phase. Theaxial location of the “ion mirror” will vary in accordance with manyparameters, including the actual design of the phases of the electrodebut in any case it is in a distance that creates the equilibrium betweenthe ions and electrons that eventually establishes the “ion mirror”.

According to some embodiments, electron emitting electrodes arecharacterized by having at least two phases whereby phase arrangement isdesigned to induce ion and electron “clouds” in vicinity of electrode,whereby at least one phase is considerably larger in diameter incomparison with the other phase of the electrode.

According to some embodiments, electron emitting electrodes arecharacterized by having at least two phases whereby phase arrangement isdesigned to induce ion and electron “clouds” in vicinity of electrode,whereby through some of the phases electric current is driven and othersare electro-statically charged.

According to some embodiments, electron emitting electrodes are arrangedin a manner generating “electric mirrors” within chamber substantiallyreducing ion “escape” at ends of tubular chamber.

Operation of the currently contemplated system requires relatively smallenergy level input from external sources (compared to conventionalsystems) both for heating and for magnetic field build-up. A personskilled in the art would appreciate that implementing the unique designcriteria derived from the approaches described hereinabove will presenta highly efficient system.

Without limitation of any of hereinabove, a person skilled in the artwould appreciate that the harvestable plasma obtainable in accordancewith the suggested system and method may be used as a neutron source, asa source for extreme UV, in an etching process, energy harvesting and/orgenerally in or for high density high temperature plasma fusionprocesses.

Although the present invention has been described with reference tospecific embodiments, this description is not meant to be construed in alimited sense. Various modifications of the disclosed embodiments, aswell as alternative embodiments of the invention will become apparent topersons skilled in the art upon reference to the description of theinvention. It is, therefore, contemplated that the appended claims willcover such modifications that fall within the scope of the invention.

The invention claimed is:
 1. A method for stably confining a plasma in a cylindrical chamber comprising the steps of: injecting a gas into the cylindrical chamber; applying a magnetic field about a portion of the cylindrical chamber; applying an electric potential between a first anode and at least one cathode to create a radial electric field within the cylindrical chamber, wherein the first anode is generally radially arranged around a central axis of the cylindrical chamber and in proximity to a wall of the cylindrical chamber, and wherein the at least one cathode is located on the central axis of the cylindrical chamber and at a distal end of the cylindrical chamber, wherein a second anode comprising a cylindrical metallic mesh grid is generally radially arranged around the central axis of the cylindrical chamber between the first anode and the central axis of the cylindrical chamber; and injecting electrons into the chamber from the at least one cathode to create a virtual cathode along the central axis of the cylindrical chamber; wherein, the magnetic field and the radial electrical field accelerate ion movement toward the central axis of the cylindrical chamber to facilitate ion collisions, whereby an increase of ion movement towards the central axis of the cylindrical chamber substantially contributes to an ion heating and to a rotation of the plasma therein, thereby increasing a stability and a confinement of the plasma.
 2. The method of claim 1 wherein the ion heating is further increased by adiabatic compression.
 3. The method of claim 1, further comprising the following steps: a. creating a substantially reduced internal pressure in the cylindrical chamber; and creating ion clouds at a distal end of the cylindrical chamber by injecting electrons from the at least one cathode wherein radial ion acceleration in the cylindrical chamber from the wall of the cylindrical chamber to the central axis of the cylindrical chamber is affected whereby ion collisions are facilitated at the central axis of the cylindrical chamber.
 4. The method of claim 3 wherein an ion density in the cylindrical chamber is enhanced by inserting a gas proximal to the chamber wall.
 5. The method of claim 1 wherein the acceleration of ion movement is enhanced by the second anode radially arranged along the central axis of the cylindrical chamber and closer to the central axis of the cylindrical chamber than the first anode.
 6. The method of claim 5 wherein the second anode is a conductive apparatus placed at a radius from the central axis of the cylindrical chamber proximal to a main reaction stage.
 7. The method of claim 6 wherein the second anode has mesh density in the range of 0% to 15% and less than 5%.
 8. The method of claim 6 wherein the conductive apparatus is made of high temperature resistant materials such as stainless steel, tungsten or molybdenum.
 9. The method of claim 5 wherein the second anode is placed at an axial plasma boundary area between an outer ionization stage and a main reaction stage.
 10. The method of claim 1 wherein the stably confined plasma is harvested as a neutron, UV, extreme UV or energy source.
 11. The method of claim 1 wherein a means for applying the magnetic field about a portion of the cylindrical chamber is coupled with a capacitor bank.
 12. The method of claim 11 wherein a substantially long current pulse is applied to the means for applying the magnetic field about a portion of the cylindrical chamber.
 13. The method of claim 1 wherein plasma stability and confinement is improved by controlling the gas injection into the cylindrical chamber during operation of the method.
 14. The method of claim 1 wherein the radial electric field at the central axis of the cylindrical chamber is affected by the at least one cathode.
 15. The method of claim 14 wherein heat concentrated at a tip of the at least one cathode causes an additional emission of electrons in a thermionic emission process affecting the strength of the radial electric field and wherein ions and electrons are held by the magnetic field towards the midpoint between distal ends of the cylindrical chamber.
 16. A system for stably confining a plasma, comprising: a. a cylindrical chamber; b. a first anode in proximity of a wall of the cylindrical chamber; c. at least one cathode at a distal end of the cylindrical chamber and at a central axis of the cylindrical chamber; d. a means for generating a magnetic field in the cylindrical chamber; e. capacitor banks dischargeable into a chamber volume; f. a pre-heating electric power supply coupled with the at least one cathode in the cylindrical chamber; g. a working gas source coupled into the cylindrical chamber; h. a second anode comprising a cylindrical metallic mesh grid and generally radially arranged around the central axis of the cylindrical chamber between the first anode and the central axis of the cylindrical chamber; i. a controlling unit connected to the first anode, the second anode, the at least one cathode, the generating means, the capacitor banks, the pre-heating electric power supply, and the working gas source; whereby the control unit controls a first voltage applied between the first anode and the at least one cathode, a second voltage applied between the second anode and the at least one cathode, a generated magnetic field, the working gas, and a power applied to the pre-heating electric power supply to produce ion movement towards the central axis of the cylindrical chamber and to heat ions in the cylindrical chamber and also to produce a rotation of the plasma therein, bringing about an increase of stability and a confinement of the plasma. 